Cast Rite of Replication by paying ({2} magic symbol) ({U} magic symbol) ({U} magic symbol) , targeting Mondrak.
Vesuvan Duplimancy triggers, creating two nonlegendary token copies of Mondrak.
Resolve Rite of Replication, creating eight copies of Mondrak.
Put all but one legendary Mondrak into your graveyard due to the legend rule.
When the Mondraks die, Ratadrabik triggers eight times.
Resolve the first Ratadrabik trigger, creating a number of nonlegendary token copies of Mondrak equal to 2^(the number of Mondraks you currently control) that are 2/2 Zombies in addition to their other types.